Rapid prototyping is a generic name of various technologies for producing three-dimensional models, usually from three-dimensional CAD (Computer Aided Design) data.
One such technology is known in the art as three-dimensional printing, in which layers descriptive of the model are produced from the CAD data, then a curable liquid material, usually a photopolymer, is dispensed and cured layer by layer by exposure to light.
One such technique is disclosed in U.S. application Ser. No., 09/412,618 assigned to the applicants of the present invention, filed Oct. 6, 1999, entitled “SYSTEM AND METHOD FOR THREE DIMENSIONAL MODEL PRINTING,” incorporated herein by reference.
According to certain embodiments described in Ser. No. 09/412,618, the model is produced from a building material (BM), which is a curable liquid photopolymer, dispensed by ink jet multi-nozzle beads. Simultaneously with the BM dispensing, a second set of ink jet heads dispenses Support Material (SM), which exhibit different properties from those of the BM.
Preferably, the SM is dispensed in locations where BM is absent, thus holding the liquid BM in place until being cured. At the conclusion of the model production, the SM is to be disposed without spoiling the model.
There are many techniques, known in the art, for SM removal, which depend on the material properties. Using wax, for instance, as SM, enables SM removing by raising the model temperature beyond the melting point of the SM.
Another known technique is stereolithography, in which use is made of a single curable material in a container, curing selectively only those portions required to form the model, the uncured portions are used as support materials and are removed at a later stage. This technique is disclosed by for example U.S. Pat. No. 5,779,967 to Hull.
Rapid prototyping (RP) techniques are known in the art as techniques used to produce models out of three-dimensional CAD data. In the same way, rapid tooling (RT) manufacturing techniques are generally used for rapid manufacturing of casting molds. Rapid manufacturing (RM) techniques are generally used for direct manufacturing of finished parts.
In all of these prior art techniques the unnecessary part (i.e. the support, the mold or the core) should be disposed, leaving the other part intact. In these above-mentioned techniques, the materials used as SM do not exhibit the optimal combination of properties required, i.e. easy dispensing, toughness as supporting material, easy removal from the finished model and friendliness to the environment. Thus, there is a strong need in the art for new and better materials that can be used to support 3-dimensional objects during construction.